Pressure sensing device



July 10, 1962 H. LANGSTROTH PRESSURE SENSING DEVICE Original Filed Oct. 9, 1956 mverrron:

HALL LANGSTROTH United States Patent 3,043,339 PRESSURE SENSING DEVICE Hali Langstroth, 1454 Alegriano Ave., Coral Gables, Fla. Original apptication Oct. 9, 1956, Ser. No. 621,333, now Patent No. 2,950,421, dated Aug. 23, 1960. Divided and this application May 18, 1959, Ser. No. 814,090 3 Claims. (Cl. 137-788) This invention relates to a pressure sensing device useful for the measurement of pressure to a high degree of accuracy. More specifically, this invention relates to a pressure sensing device which utilizes' a protected diaphragm to sense pressure changes, being useful at high pressure levels where the unsupported bellows type sensing element would fail to function.

This application is a division of my copending application Serial No. 621,333 filed October 9, 1956, now Patent 2,950,421 to which reference may be had for a more complete explanation of the use of the device claimed herein.

The present invention eliminates the requirement for alignment shafts thereby reducing friction to a minimum. The pressure range is easily changed externally by an adjustment nut which varies the spring pressure and the pressure range of the device.

Further objects will appear from the following description and appended claims when read in conjunction with the accompanying drawing wherein:

The single FIGURE is a vertical sectional view illustrating a preferred embodiment of the present invention.

For a better understanding of the present invention reference is made to the drawing in which tubular member 65 is an integral part of flange 66, the inner surface 79 of tubular member 65 is threaded to engage a supply line. The opposite half 68 is disc shaped of the same flange diameter as flange 66. Aflixed to diaphragm 67 are members 69 and 70 which extend in opposite directions and which are joined to the diaphragm 67 being hermetically sealed at this junction preferably by brazing. Flanges 68 and 66 form two halves of a closure between which is placed diaphragm 67 and associated members 69 and 70. The outer periphery of flanges 66, 68 and diaphragm 67 are hermetically sealed together preferably by brazing. A vacuum tight wall is thereby completed by the flexible diaphragm 67. The members 66 and 68 form a cavity in which diaphragm 67 is free to move.

Member 70 extends through an axial opening in member 68, member 70 acting as a piston to move electrical or mechanical sensing elements. The member 69 is made to extend outwardly and is terminated in an axially extending stud member 72 arranged in the axis of the tubular member 65. Stud member 72 is threaded to receive nut 73. Opposed to the inner surface of nut 73 is a shoulder 74 and a spring 75 is arranged to extend between these opposed surfaces. The spring 75 urges the diaphragm to resist pressure applied through the axis of tubular member 65 by adjusting nut 73 or by changing spring 75. The pressure set point can be varied for dif-- ferent pressure levels by this means. To the end of member 70 is attached an insulator 71 which is attached to contact arm 12 to make or break electrical contacts.

The enclosure formed by members 66 and 68 provide protection against overloading diaphragm 67 being made to present a shear free enclosure for the diaphragm. Radially spaced grooves 76 are provided in diaphragm 67 to add flexibility. These grooves can be formed by applying the proper gas or fluid pressure on either side of the diaphragm. Annular grooves 77 and mating annular projections 78 are provided in the opposing faces of enclosure members 66 and 68 for this function. It has been found it best to install plain flat disc or partially formed diaphragms and subject them to over pressures "ice after assembly to eliminate unprcdictably snap action oil can affect which can seriously affect the pressure point. Members 69 and 70 joined with diaphragm 67 have conical tapered flanges when fully seated in either direction, mating conical recesses are provided in the same axis of flange members 66 and 68. This construction presents a shear free surface to the diaphragms exposed surfaces. The conical tapered section on members 69 and 70 seat flush with the inside surfaces of members 66 and 68 presenting a shear free surface. It is advisable to lap fit these members to assure proper seating.

The end of member 70 can be connected to electrical or other types of pressure sensing elements to indicate a change in the pressure level, in response to the pressure applied, providing attachment means for pressure sensing elements.

It is understood that, although the invention has been described with specific reference to particular embodiments thereof, it is not so limited since changes and alterations therein may be made which are within the full intended scope of this invention as defined by the appended claims.

What is claimed and desired to be secured by United States Letters Patent is:

1. A pressure sensing device comprising rigid top and bottom housing sections having opposingly dished wall surfaces peripherally delimited by opposing clamp faces; a flexible diaphragm having a peripheral marginal area clamp sealed between the peripheral clamp faces of the dished Wall surfaces of said housing sections with its central body portion free to move in opposite directions between said dished wall surfaces, said wall surfaces being respectively formed to provide shear free abutment surfaces for the major portion of said central body portion and centrally centered passages therethrough terminating at their intersections with said wall surfaces in internally oppositely facing recessed seats; respective centrally located shafts having sealed connection with the midportion of said central body portion, oppositely facing seating formations on said shaft adapted for mating arresting engagement in the respective recessed seats in said housing wall surfaces and respective shaft portions extending through said centered passages; means adapting one of said centered passages for connection to an input pressure source and to abuttingly engage a biasing spring; spring means connected to the shaft portion in said one centered passage and reacting against said passage adapting means to oppose the input pressure acting in one direction and maintain said central body portion in a predetermined position between said housing sections; and means adapting the other shaft portion for connection to a suitable sensing element for sensing movements of said diaphragm and body in response to variations in input pressure, said contoured Walls and said mating shaft seating formations cooperating to form an uninterrupted backing surface engageable, upon excessive pressure deflection of said diaphragm in either direction, to rigidly back up said diaphragm over its entire central body portion and prevent rupture of the. diaphragm.

2. A pressure sensing device providing a shear proof backing for a diaphragm comprising a chambered housing formed by a pair of rigid housing members having opposed shallow dished chamber defining faces formed at their respective centers with an opening defining sloping seat wall portion, at their respective peripheries with opposing marginal annular clamp faces and radially therebetween with opposing annular groove and rib formations; a flexible diaphragm edge clamped between said marginal annular clamp faces with its central body portion spanning the opposed chambers of said housing members and annularly deformed in opposed relation to said groove and rib formations of said housing members thereby adapting said body portion, upon application of excessive pressure to one face of said body portion, to move into full seated backed engagement with the chamber defining face of a respective one of the opposed housing members; respective flanged shaft members clampingly fixed in centered relation to the body portion of said flexible diaphragm and having oppositely directed seat faces formed to respectively matingly abuttingly engage and fill up said sloping seat wall portions, said shaft flanges serving to close off any through opening in said chamber defining faces upon application of diaphragm actuating fluid pressure in excess of that for which the diaphragm is designed; adjustable means acting on one of said flanged shaft members to load said diaphragm body portion and establish a resistance to fluid pressure movement of said diaphragm in one direction; means carried by the other of said flanged shaft members and extending through its related housing opening for actuating an indicator to indicate the fluid pressure deflection of said diaphragm body portion; and means for connecting one side of said diaphragm through the opening in one of said sloping seat wall portions to a source of pressurized fluid to be sensed.

3. The pressure sensing device of claim 2 wherein said I adjustable means comprises a coil spring one end of which abuts the back face of the opening defining Wall portion of one of said housing members and a spring retainer nut threaded on said one flanged shaft member and abuttingly engaging the other coil spring end and wherein the means connecting one side of said diaphragm to a source of pressurized fluid comprises an internally threaded boss formed on said one housing member in enclosing relation to said coil spring and in communication with the center opening in said one housing member.

References Cited in the file of this patent UNITED STATES PATENTS 466,275 Fasoldt Dec. 29, 1891 1,579,536 Hodgson Apr. 6, 1926 1,806,791 Davis May 26, 1931 1,909,038 Arthur May 16, 1933 2,605,749 Buckendale Aug. 5, 1952 2,762,394 Hastings Sept. 11, 1956 

